Development of a Novel Vapor Deposited Silica Sol Particles for Use as a Bioactive Materials System

INTRODUCTION Because of their mild processing conditions and inherent biocompatibility, silica sol gels are becoming increasingly popular for use in tissue engineering, especially orthopedic applications. In addition to substantial biocompatibility, these materials have the potential to serve as delivery vehicles for various organic and inorganic molecules, including calcium and phosphate ions, the primary constituents of mineral species found in bone. The overall goal of this work is to develop a novel nebulizer-based vaporization method to generate sol gel particles for use as a biologically active materials system. The system can be used to facilitate the biomimetic modification (chemical and physical properties) of traditional orthopedic biomaterials and tissue engineering constructs. The chemical (composition, stability, hydrophobicity, surface charge) and physical (size distribution, morphology, roughness, topography) properties of the particles are dependent upon many parameters including sol formulation (H2O:alkyloxide ratio, pH, aging time, addition of secondary inorganic and organic molecules), production parameters (air pressure, vaporization time), and underlying substrate character. The objective of this study is to establish dimensional analysis methods for our sol particles and to evaluate the effects of key parameters on particle chemical-physical properties as a means for their rational use in orthopedic implant materials and tissue engineering.